PROJECT SUMMARY: CORE A Core A is the Administrative and Clinical Acquisition Core for the PPG and all of its components. This PPG includes outstanding scientists within the Blood Research Institute and in Kingston Ontario, Dublin, and the University of Colorado, that are tightly focused on the biology of von Willebrand factor (VWF) and mechanisms causing von Willebrand Disease (VWD). Aim 1 is to effectively handle the administrative interactions between the 4 projects and 3 cores. Core A will schedule the periodic (monthly) conference calls between principal investigators as well as the two in-person meetings held at ASH and ISTH. Aim 2 will efficiently handle the clinical acquisition of samples, maintain the biorepository, assure the integrity and confidentiality of the database. It will also handle the shipment of DNA or plasma samples from the Milwaukee center to the selective projects (1, 2, 3, and 4) and Cores B and C. Core A will also maintain open and effective communication with the administrative and fiscal responsible personnel at all of the collaborating centers and NIH.